US6129987AExpiredUtility

Method of making a piece of glass for measuring transmittance

32
Assignee: NIKON CORPPriority: Sep 8, 1994Filed: Apr 23, 1998Granted: Oct 10, 2000
Est. expirySep 8, 2014(expired)· nominal 20-yr term from priority
Inventors:Hiroki JinboSatoru OshikawaHiroyuki Hiraiwa
G01N 21/5907
32
PatentIndex Score
2
Cited by
19
References
18
Claims

Abstract

In the measurement of internal transmittance of optical pieces, a standard is set for the piece for measuring the transmittance and a method of making the piece is provided. In the piece for measuring the Transmittance of optical materials having two opposing polished surfaces, their surface roughness rms is set to 10 Å or less, thereby making it possible to accurately measure the internal transmittance in the short wavelength region of 300 nm or less where the intensity of the light source of spectrophotometer begins to decrease.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A silica glass piece having two flat surfaces opposing each other, wherein, (a) each of said two flat surfaces has a surface roughness of 10 angstroms or less; and   (b) the transmittance of said silica glass piece is not less than 0.910 cm -1  and not more than 0.921 cm -1  with respect to a light beam having a wavelength of 248 nm.   
     
     
       2. A silica glass piece according to claim 1, wherein an angle between said two flat surfaces is 30 second or less. 
     
     
       3. A silica glass piece according to claim 1 wherein an amount of undesired Ce is 4×10 12  atoms/cm 2  or less. 
     
     
       4. A silica glass piece having two flat surfaces opposing each other, wherein, (a) each of said two flat surfaces has a surface roughness of 10 angstroms or less; and   (b) the transmittance of said silica glass piece is not less than 0.895 cm -1  and not more than 0.908 cm -1  with respect to a light beam having a wavelength of 193 nm.   
     
     
       5. A silica glass piece having two flat surfaces opposing each other, wherein, (a) each of said two flat surfaces has a surface roughness of 10 angstroms or less; and   (b) the transmittance of said silica glass piece is not less than 0.9210 cm -1  and not more than 0.9211 cm -1  with respect to a light beam having a wavelength of 248 nm.   
     
     
       6. A silica glass piece according to claim 4, wherein the transmittance of said silica glass piece is not less than 0.905 cm -1  and not more than 0.908 cm -1  with respect to a light beam having a wavelength of 193 nm. 
     
     
       7. A silica glass piece according to claim 1, wherein said piece satisfies the following expression: A+B<4368 nm   where,   A is the distance between two maximally separated parallel virtual planes on one of said flat surfaces; and   B is the distance between two maximally separated parallel virtual planes on the other of said flat surfaces is the distance between two maximally separated parallel virtual planes on one of said flat surfaces.   
     
     
       8. A silica glass piece according to claim 1, comprising: two side surfaces continuous to each other, said two side surfaces connecting peripheries of said two flat surfaces, one of said side surfaces curving around the peripheries of said two flat surfaces, the other side surface being flat causing said silica glass piece to have the shape of flattened cylinder.   
     
     
       9. A silica glass piece according to claim 8, wherein the circumferential angle of said curving side surface is greater than 270°. 
     
     
       10. A piece having two flat surfaces opposing each other, wherein, (a) each of said two flat surfaces has a surface roughness of 10 angstroms or less; and   (b) the transmittance of said piece is not less than 0.910 cm -1  and not more than 0.921 cm -1  with respect to a light beam having a wavelength of 248 nm.   
     
     
       11. A piece according to claim 10, wherein an angle between said two flat surfaces is 30 second or less. 
     
     
       12. A piece according to claim 10, wherein an amount of undesired Ce is 4×10 12  atoms/cm 2  or less. 
     
     
       13. A piece having two flat surfaces opposing each other, wherein, (a) each of said two flat surfaces has a surface roughness of 10 angstroms or less; and   (b) the transmittance of said piece is not less than 0.895 cm -1  and not more than 0.908 cm -1  with respect to a light beam having a wavelength of 193 nm.   
     
     
       14. A piece having two flat surfaces opposing each other, wherein, (a) each of said two flat surfaces has a surface roughness of 10 angstroms or less; and   (b) the transmittance of said piece is not less than 0.9210 cm -1  and not more than 0.9211 cm -1  with respect to a light beam having a wavelength of 248 nm.   
     
     
       15. A piece according to claim 10, wherein the transmittance of said piece is not less than 0.905 cm -1  and not more than 0.908 cm -1  with respect to a light beam having a wavelength of 193 nm. 
     
     
       16. A piece according to claim 10, wherein said piece satisfies the following expression: A+B<4368 nm;   where;   A is the distance between two maximally separated parallel virtual planes on one of said flat surfaces; and   B is the distance between two maximally separated parallel virtual planes on the other of said flat surfaces is the distance between two maximally separated parallel virtual planes on one of said flat surfaces.   
     
     
       17. A piece according to claim 10, comprising: two side surfaces continuous to each other, said two side surfaces connecting peripheries of said two flat surfaces, one of said side surfaces curving around the peripheries of said two flat surfaces, the other side surface being flat causing said piece to have the shape of flattened cylinder.   
     
     
       18. A piece according to claim 17, wherein the circumferential angle of said curving side surface is greater than 270°.

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